The invention relates to a speed control governor for vehicle engines, particularly diesel engines for heavy goods vehicles or the like, having a gear shift mechanism and a fuel supply means such as a fuel pump with a spindle which regulates the supply of fuel and is connected to a coupling member which is controlled by the accelerator pedal, an end abutment being provided to limit the maximum movement of the coupling member and thereby define the angular end position of the fuel pump regulating spindle corresponding to maximum engine speed.
In general, diesel engines of heavy goods vehicles or the like have a predetermined maximum speed which can be adjusted to the value desired for any particular engine by adjusting the maximum speed stop for the regulating lever of the fuel pump. This maximum speed can thus be selected so that in the lower gears with the throttle wide open the engine can produce sufficient power to enable the vehicle to be accelerated as much as possible without damaging the engine. If however, when travelling on motorways or the like, the driver fully depresses the accelerator pedal in top gear so that for prolonged periods the engine rotates at the maximum speed of, for example, 2500 r.p.m., then this may lead to increased wear and, under certain circumstances, to serious damage to the engine, quite apart from the fact that driving, when fully laden, at maximum speeds is dangerous and entails an uneconomical fuel consumption. It is therefore highly desirable to ensure that when travelling in top gear the maximum speed of the engine can automatically be set to a lower value of, for example, 2200 r.p.m.